Light scattered from a target is the most-direct measurement for diagnosing laser absorption in a direct-drive implosion. Observations from OMEGA implosions show much larger scattered-light asymmetries than predictions. A new instrument has been developed to absolutely measure the scattered-light intensity and nonuniformity for the purpose of diagnosing the asymmetry. The scattered-light uniformity imager (SLUI) diagnostic records the variation in scattered-light intensity over a transmission diffuser using a charge-coupled device (CCD)/lens assembly. At the standard operating position, an 11.3° (f/2.5) cone of light is collected. A stray light baffle, debris shield, and antireflection absorbing filter are also incorporated into the diagnostic payload inserted into the target chamber. The imaging parts of the diagnostic (light baffle, vacuum window, filters, lens, and CCD camera) are located outside the target chamber. Five SLUIs have been built and deployed in OMEGA's ten-inch manipulator diagnostic ports, covering almost 5% of the emission surface, enabling an absolute scattered-light measurement should be within a few percent of the global average. Each SLUI system is calibrated offline, providing absolute scattered-light intensity measurements. Based on the measured point spread function, each diffuser plate image contains over 20 000 independent scattered-light absolute-intensity measurements of the variation over the collection cone. SLUI provides a platform to study scattered light and absorption asymmetries, and their possible sources.
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http://dx.doi.org/10.1063/5.0101798 | DOI Listing |
Using a full-wave theory to analyze the light beam scattering at sharp interfaces, we reexamine the anomalous spin-orbit interaction (SOI) around the Fresnel coefficient (FC) singularities. We evaluate the spin-dependent beam shifts near the singularity for three typical optical interfaces, comparing our results with existing ones. Existing theories neglect the contribution of the wave vector component near the FC singularities, potentially leading to erroneous results.
View Article and Find Full Text PDFMass Spectrom Rev
December 2024
Institut de Recherche Interdisciplinaire de Grenoble (IRIG), CEA, Grenoble, France.
Single particle mass analysis methods allow the measurement and characterization of individual nanoparticles, viral particles, as well as biomolecules like protein aggregates and complexes. Several key benefits are associated with the ability to analyze individual particles rather than bulk samples, such as high sensitivity and low detection limits, and virtually unlimited dynamic range, as this figure of merit strictly depends on analysis time. However, data processing and interpretation of single particle data can be complex, often requiring advanced algorithms and machine learning approaches.
View Article and Find Full Text PDFNanophotonics
March 2024
Department of Photonics, National Cheng Kung University, Tainan 70101, Taiwan.
While conventional optical sensors hold historical significance, they face inherent limitations in sensitivity, operational intricacies, and bulky size. A breakthrough in this realm comes from the advent of metasurface sensors, which leverage nanoscale optical effects, thereby expanding the horizons of optical sensing applications. However, past methods employed in metasurface sensors predominantly rely on wavelength shifts or intensity changes with high- resonances, thereby significantly restricting the detection bandwidth.
View Article and Find Full Text PDFACS Omega
November 2024
Advanced Laboratory of Electro-Optics (ALEO), Department of Applied Physics/Electro-Optics Engineering, Lev Academic Center, Jerusalem 9116001, Israel.
Plasmonic nanostructure arrays, designed for performance as pixels in an advanced SERS imaging device, were fabricated by gallium focused ion beam (FIB). Though the FIB is best suited for etching holes and negative structures, our previously reported simulations favor protrusions. Herein, we report on the FIB methodology to "sculpt" positive structures by "ion-blasting" away the surrounding material.
View Article and Find Full Text PDFPlants (Basel)
November 2024
Department of Biophysics, N.I. Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia.
Remote sensing plays an important role in plant cultivation and ecological monitoring. This sensing is often based on measuring spectra of leaf reflectance, which are dependent on morphological, biochemical, and physiological characteristics of plants. However, interpretation of the reflectance spectra requires the development of new tools to analyze relations between plant characteristics and leaf reflectance.
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